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| 2. |
- Chang, WR, et al.
(författare)
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The role of friction in the measurement of slipperiness, Part 1 : Friction mechanisms and definition of test conditions
- 2001
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Ingår i: Ergonomics. - 0014-0139 .- 1366-5847. ; 44:13, s. 1217-1232
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Tidskriftsartikel (refereegranskat)abstract
- Friction has been widely used as a measure of slipperiness. However, controversies around friction measurements remain. The purposes of this paper are to summarize understanding about friction measurement related to slipperiness assessment of shoe and floor interface and to define test conditions based on biomechanical observations. In addition, friction mechanisms at shoe and floor interface on dry, liquid and solid contaminated, and on icy surfaces are discussed. It is concluded that static friction measurement, by the traditional use of a drag-type device, is only suitable for dry and clean surfaces, and dynamic and transition friction methods are needed to properly estimate the potential risk on contaminated surfaces. Furthermore, at least some of the conditions at the shoe/floor interface during actual slip accidents should be replicated as test conditions for friction measurements, such as sliding speed, contact pressure and normal force build-up rate.
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| 3. |
- Chang, WR, et al.
(författare)
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The role of friction in the measurement of slipperiness, Part 2 : Survey of friction measurement devices
- 2001
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Ingår i: Ergonomics. - 0014-0139 .- 1366-5847. ; 44:13, s. 1233-1261
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Tidskriftsartikel (refereegranskat)abstract
- This paper seeks to address questions related to friction measurement such as how friction is related to human-centred assessment and actual slipping, and how repeatable friction measurements are. Commonly used devices for slipperiness measurement are surveyed and their characteristics compared with suggested test conditions from biomechanical observations summarized in Part 1. The issues of device validity, repeatability, reproducibility and usability are examined from the published literature. Friction assessment using the mechanical measurement devices described appears generally valid and reliable. However, the validity of most devices could be improved by bringing them within the range of human slipping conditions observed in biomechanical studies. Future studies should clearly describe the performance limitations of any device and its results and should consider whether the device conditions reflect these actual human slipping conditions. There is also a need for validation studies of more devices by walking experiments.
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| 7. |
- Gronqvist, R, et al.
(författare)
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Measurement of slipperiness : Fundamental concepts and definitions
- 2001
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Ingår i: Ergonomics. - 0014-0139 .- 1366-5847. ; 44:13, s. 1102-1117
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of this paper is to give an overview of basic concepts and definitions of terms related to the 'measurement of slipperiness' from the onset of a foot slide to a gradual loss of balance and a fall. Other unforeseen events prior to falls (e.g. tripping) are sparingly dealt with. The measurement of slipperiness may simply comprise an estimation of slipping hazard exposures that initiate the chain of events ultimately causing an injury. However, there is also a need to consider the human capacity to anticipate slipperiness and adapt to unsafe environments for avoiding a loss of balance and an injury. Biomechanical and human-centred measurements may be utilized for such an approach, including an evaluation of relevant safety criteria for slip/fall avoidance and procedures for validation of slip test devices. Mechanical slip testing approaches have been readily utilized to measure slipperiness in terms of friction or slip resistance but with conflicting outcomes. An improved understanding of the measurement of slipperiness paradigm seems to involve an integration of the methodologies used in several disciplines, among others. injury epidemiology, psychophysics, biomechanics, motor control, materials science and tribology.
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| 8. |
- Muller-Suur, R, et al.
(författare)
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Comparison of adenosine and exercise stress test for quantitative perfusion imaging in patients on beta-blocker therapy
- 2001
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Ingår i: Cardiology. - : S. Karger AG. - 0008-6312 .- 1421-9751. ; 95:2, s. 112-118
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Tidskriftsartikel (refereegranskat)abstract
- Beta-blocker therapy is used to decrease myocardial ischemia during exercise but may cause suboptimal diagnostic performance in exercise stress testing. The aim of the present study was to compare results of quantitative technetium-99-sestamibi single photon emission tomography (SPECT), following exercise stress test or pharmacological stress test with adenosine. We chose adenosine as comparison, since betablockers may not interfere with adenosine induced vasodilatation and therefore possibly may not interfere with its diagnostic performance. Sixteen patients with angiographically documented coronary disease (5 single-vessel, 6 two-vessel and 5 three-vessel disease), who were chronically treated with beta-blockers, performed SPECT imaging at rest, following bicycle exercise and following adenosine infusion in random order. The SPECT data were analyzed visually and quantitatively, using dedicated computer software (CEqual). According to both visual and quantitative SPECT analysis, adenosine was superior to show reversibility. Higher reversibility extent (50 ± 15 vs. 26 ± 12 pixels, p < 0.01) and more intense reversibility severity (110 ± 29 vs. 49 ± 23 sum of SDs, p < 0.05) were observed during adenosine than exercise. <i>Conclusions:</i> Less myocardial perfusion abnormalities during exercise than during adenosine stress in patients treated with beta-blockers may indicate less ischemia but also an impaired diagnostic performance. Thus adenosine stress test should be preferred to optimize the diagnostic sensitivity in patients during beta-blocker treatment.
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| 9. |
- Pedersen, T.R., et al.
(författare)
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Follow-up study of patients randomized in The Scandinavian Simvastatin Survival Study (4S) of cholesterol lowering
- 2000
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Ingår i: American Journal of Cardiology. - 0002-9149 .- 1879-1913. ; 86:3, s. 257-262
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Tidskriftsartikel (refereegranskat)abstract
- The Scandinavian Simvastatin Survival Study (4S) and other randomized clinical trials have demonstrated that cholesterol-lowering treatment with statins improves prognosis in patients with coronary atherosclerosis compared with placebo. The effect of therapy with statins beyond the typical 5 to 6 years' duration of the trials, in particular regarding the risk of cancer, has not been investigated. This study examines the long-term effects of simvastatin for up to 8 years on cause-specific mortality in patients with coronary heart disease (CHD). We performed an observational, government registry-based study of mortality in the groups originally randomized to simvastatin or placebo in the 4S over an additional 2-year follow-up period, so that the median total follow-up period was 7.4 years (range 6.9 to 8.3 in surviving patients). Randomization took place at outpatient clinics at 94 clinical centers in Denmark, Finland, Iceland, Norway, and Sweden from 1988 to 1989. Of 4,444 patients with CHD, 2,223 and 2,221 were randomized to treatment with placebo or simvastatin therapy, respectively. Patients received treatment with simvastatin, starting at 20 mg/day, with titration to 40 mg/day at 12 or 24 weeks if total cholesterol was >5.2 mmol/L (200 mg/dl), or placebo. After the double-blind period, most patients in both treatment groups received simvastatin as open-label prescription. Of the 1,967 patients originally treated with placebo and surviving the double-blind period, 97 (4.9%) died during the following 2 years. In the group randomized to simvastatin the corresponding number was 74 of the 2,039 survivors (3.6%). Adding these deaths to those occurring during the original trial, the total was 353 (15.9%) and 256 (11.5%) deaths in the groups originally randomized to placebo and simvastatin, respectively. The relative risk was 0.70 (95% confidence interval 0.60 to 0.82, p = 0.00002). The total number of cancer deaths was 68 (3.1%) in the placebo group and 52 (2.3%) in the simvastatin group (relative risk 0.73, 95% confidence interval 0.51 to 0.05, p = 0.087), and the numbers of noncardiovascular and other deaths were similar in both groups. We therefore conclude that treatment with simvastatin for up to 8 years in patients with CHD is safe and yields continued survival benefit. Copyright (C) 2000 Excerpta Medica Inc.
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| 10. |
- Strandberg, B, et al.
(författare)
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Organochlorine compounds in the Gulf of Bothnia : sediment and benthic species
- 2000
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Ingår i: Chemosphere. ; 40:9-11, s. 1205-1211
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Tidskriftsartikel (refereegranskat)abstract
- Surface sediment, amphipods (Monoporeia affinis), isopods (Saduria entomon) and fourhorn sculpins (Oncocottus quadricornis) were collected at two coastal stations in the Gulf of Bothnia, one in the Bothnian Bay and the other in the Bothnian Sea. The objective was to study the concentrations, composition profiles, bioaccumulation features and spatial differences of organochlorine compounds such as hexachlorocyclohexanes (HCHs), DDTs, hexachlorobenzene (HCBz), chlordanes (CHLs), dieldrin, Mirex and polychlorinated biphenyls (PCBs). All groups of compounds were found in every sample investigated, with the exception of Mirex that was not detected in the sediment samples. The concentrations for e.g. PCBs and CHLs ranged from 700 to 2400 and 70 to 400 ng/g lipid in the specimens. For the corresponding sediments the results were 9.0-9.3 ng/g dw for PCBs and 0.54-0.57 ng/g dw for CHLs, respectively. Bioaccumulation differences between the species with regard to both degree of and type of compound were observed. The highest accumulation potential was found for the cyclodiene compounds including CHLs and Mirex in isopod. Finally, there were only small concentration and bioaccumulation differences between the two stations.
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